What do the numbers on LED strip indicate? 

LED strip lights are manufactured according to a 4 digit code for example -  3528, 5050, 3030 and 2835. But what do they mean? well, in summary, the first two digits are referring to the width of the LED strip and the last two digits refer to the length.  As an example, a 5050 LED strip has a width of 5.0mm and a length of 5.0mm. 

LED chips are surface mounted onto flexible metal strips that perform as a heat sink, drawing heat from the chips, allowing them to stay cool when in use.